According to Greenhouse Canada: After experimenting with different media, there was a transition period where commercial growers tried the different options. Many growers in Alberta switched over to rockwool, but coir started coming into the picture in the early 2000s and many started using this as the main growing medium instead. Lately, rockwool has been gaining ground again. Growers will keep on changing their growing media based on cost, ease of handling, disposal, and other considerations.
Soilless cultivation by hydroponics is the most commonly used technique worldwide. That includes cultivation in sand, peat moss, rice hulls, gravel, and other locally available growing media. The use of coir has expanded significantly now. There are also variations of the hydroponic system, such as floating Styrofoam panels with plants, nutrient film techniques, deep flow channels, and other similar techniques.
Nutrients are delivered via drip irrigation through injectors, and leached water is drained to waste or recycled. Note that hydroponics is just another method of production and when it first came out, the benefits were often compared to production in soil. The touted benefits of using hydroponics, like less water use, lower disease pressure, and better quality crop – all should be understood in proper context and with relevant comparisons. I recall how growers in Alberta took four years to successfully switch over from soil to hydroponic systems, and only after they had gained a thorough understanding of nutrient delivery and crop management from open house demonstrations and technical manuals.